$-3de - 5df + 7d - 8 = -3e - 2$ Solve for $d$.
Answer: Combine constant terms on the right. $-3de - 5df + 7d - {8} = -3e - {2}$ $-3de - 5df + 7d = -3e + {6}$ Notice that all the terms on the left-hand side of the equation have $d$ in them. $-3{d}e - 5{d}f + 7{d} = -3e + 6$ Factor out the $d$ ${d} \cdot \left( -3e - 5f + 7 \right) = -3e + 6$ Isolate the $d$ $d \cdot \left( -{3e - 5f + 7} \right) = -3e + 6$ $d = \dfrac{ -3e + 6 }{ -{3e - 5f + 7} }$ We can simplify this by multiplying the top and bottom by $-1$. $d= \dfrac{3e - 6}{3e + 5f - 7}$